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Single line segments with rounded ends

Source: R/geom_leg.R
geom_leg.Rd

This is ggplot2's segment with rounded ends. It's mainly included in ggmap for historical reasons.

Usage

geom_leg(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  arrow = NULL,
  lineend = "round",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  ...
)

Arguments

mapping

Set of aesthetic mappings created by aes(). If specified and inherit.aes = TRUE (the default), it is combined with the default mapping at the top level of the plot. You must supply mapping if there is no plot mapping.

data

The data to be displayed in this layer. There are three options:

If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot().

A data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See fortify() for which variables will be created.

A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data. A function can be created from a formula (e.g. ~ head(.x, 10)).

stat

The statistical transformation to use on the data for this layer, either as a ggproto Geom subclass or as a string naming the stat stripped of the stat_ prefix (e.g. "count" rather than "stat_count")

position

Position adjustment, either as a string naming the adjustment (e.g. "jitter" to use position_jitter), or the result of a call to a position adjustment function. Use the latter if you need to change the settings of the adjustment.

arrow

specification for arrow heads, as created by grid::arrow().

lineend

Line end style (round, butt, square).

na.rm

If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.

show.legend

logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes. It can also be a named logical vector to finely select the aesthetics to display.

inherit.aes

If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. borders().

...

Other arguments passed on to layer(). These are often aesthetics, used to set an aesthetic to a fixed value, like colour = "red" or size = 3. They may also be parameters to the paired geom/stat.

Details

only intended for use in ggmap package. only designed for mercator projection.

See also

geom_segment(), route(), inspired by http://spatialanalysis.co.uk/2012/02/great-maps-ggplot2/, no longer active

Examples


if (FALSE)  # removed for R CMD check speed

map <- get_map(
  location = c(-77.0425, 38.8925), # painfully picked by hand
  source = "google", zoom = 14, maptype = "satellite"
)
ggmap(map)
#> Error in eval(expr, envir, enclos): object 'map' not found


(legs_df <- route(
  "the white house, dc",
  "lincoln memorial washington dc",
  alternatives = TRUE
))
#> Error in route("the white house, dc", "lincoln memorial washington dc",     alternatives = TRUE): Google now requires an API key; see `ggmap::register_google()`.

ggplot(data = legs_df) +
  geom_leg(aes(
    x = start_lon, xend = end_lon,
    y = start_lat, yend = end_lat
  )) +
  coord_map()
#> Error in eval(expr, envir, enclos): object 'legs_df' not found

ggplot(data = legs_df) +
  geom_leg(aes(
    x = start_lon, xend = end_lon,
    y = start_lat, yend = end_lat,
    color = route
  )) +
  coord_map()
#> Error in eval(expr, envir, enclos): object 'legs_df' not found


ggmap(map) +
  geom_leg(
    aes(
      x = start_lon, xend = end_lon,
      y = start_lat, yend = end_lat
    ),
    data = legs_df, color = "red"
  )
#> Error in eval(expr, envir, enclos): object 'map' not found

# adding a color aesthetic errors because of a base-layer problem
# ggmap(map) +
#   geom_leg(
#     aes(
#       x = start_lon, xend = end_lon,
#       y = start_lat, yend = end_lat,
#       color = route
#   )
# )


# this is probably the easiest hack to fix it
ggplot(data = legs_df) +
  inset_ggmap(map) +
  geom_leg(
    aes(
      x = start_lon, xend = end_lon,
      y = start_lat, yend = end_lat,
      color = route
    ),
    data = legs_df
  ) +
  coord_map()
#> Error in eval(expr, envir, enclos): object 'legs_df' not found